Download PDF (9.49MB) - the School of Engineering and Applied ...

WWW.SEAS.UPENN.EDU
The Nano Guru
By Janelle Weaver
Films made of nanoparticles are a crucial component
found in everything from lithium ion batteries and
solar cells to the next generation of display devices
and anti-fogging coatings for automobile windshields.
One vexing problem facing engineers is that cracks
routinely form in nanoparticle films during formation,
interfering with their ability to work properly.
Traditional techniques to prevent crack formation, such
as adding substances to make the films stronger, can
also compromise their function.
With the goal of developing stronger, tougher
nanoparticle films, Daeyeon Lee, assistant professor
of Chemical and Biomolecular Engineering, recently
reported a new method to tackle this problem. By
stacking multiple, thin nanoparticle layers while
making films, he discovered that it’s possible to prevent
the formation of cracks. Lee is also exploring ways to
enhance the damage tolerance of nanoparticle films
using non-spherical nanoparticles. He envisions this
approach being useful for the development of flexible
solar cells and batteries as well as other electrical and
optical devices that can resist cracking in response to
mechanical stress.
Despite the technical nature of this research, Lee loves
to give playful summaries of his own work, according
to Ph.D. candidate Kwadwo Tettey, who joined the
lab in the spring of 2009. “Recently, he gave a talk at
a venue in Philadelphia entitled Beers, Bubbles, and
Beyond,” Tettey says. “It’s interesting to see that he
could break down his research to a very broad audience.
He does this really well, and with a sense of humor.”
Lee’s enthusiasm for science is contagious in the lab,
Tettey adds. “He’s a really engaging person and very
passionate about research in general. This attitude
rubs off on his students and keeps them motivated.”
Tettey is also inspired by Lee’s approach to scientific
problem solving. “He likes to know why something
SPRING 2013 n 6